The development of the human cerebral cortex is a complex and dynamic process, in which neural stem cell proliferation, neuronal migration, and post-migratory neuronal organization need to occur in a well-organized fashion. Alterations at any of these crucial stages can result in malformations of cortical development (MCDs), a group of genetically heterogeneous neurodevelopmental disorders that present with developmental delay, intellectual disability and epilepsy. Recent progress in genetic technologies, such as next generation sequencing, most often focusing on all protein-coding exons (e.g., whole exome sequencing), allowed the discovery of more than a 100 genes associated with various types of MCDs. Although this has considerably increased the diagnostic yield, most MCD cases remain unexplained. As Whole Exome Sequencing investigates only a minor part of the human genome (1–2%), it is likely that patients, in which no disease-causing mutation has been identified, could harbor mutations in genomic regions beyond the exome. Even though functional annotation of non-coding regions is still lagging behind that of protein-coding genes, tremendous progress has been made in the field of gene regulation. One group of non-coding regulatory regions are enhancers, which can be distantly located upstream or downstream of genes and which can mediate temporal and tissue-specific transcriptional control via long-distance interactions with promoter regions. Although some examples exist in literature that link alterations of enhancers to genetic disorders, a widespread appreciation of the putative roles of these sequences in MCDs is still lacking. Here, we summarize the current state of knowledge on cis -regulatory regions and discuss novel technologies such as massively-parallel reporter assay systems, CRISPR-Cas9-based screens and computational approaches that help to further elucidate the emerging role of the non-coding genome in disease. Moreover, we discuss existing literature on mutations or copy number alterations of regulatory regions involved in brain development. We foresee that the future implementation of the knowledge obtained through ongoing gene regulation studies will benefit patients and will provide an explanation to part of the missing heritability of MCDs and other genetic disorders.

BackgroundSNP panels that uniquely identify an individual are useful for genetic and forensic research. Previously recommended SNP panels are based on DNA profiles and mostly contain intragenic SNPs. With the increasing interest in RNA expression profiles, we aimed for establishing a SNP panel for both DNA and RNA-based genotyping.ResultsTo determine a small set of SNPs with maximally discriminative power, genotype calls were obtained from DNA and blood-derived RNA sequencing data belonging to healthy, geographically dispersed, Dutch individuals. SNPs were selected based on different criteria like genotype call rate, minor allele frequency, Hardy–Weinberg equilibrium and linkage disequilibrium. A panel of 50 SNPs was sufficient to identify an individual uniquely: the probability of identity was 6.9 × 10− 20 when assuming no family relations and 1.2 × 10− 10 when accounting for the presence of full sibs. The ability of the SNP panel to uniquely identify individuals on DNA and RNA level was validated in an independent population dataset. The panel is applicable to individuals from European descent, with slightly lower power in non-Europeans. Whereas most of the genes containing the 50 SNPs are expressed in various tissues, our SNP panel needs optimization for other tissues than blood.ConclusionsThis first DNA/RNA SNP panel will be useful to identify sample mix-ups in biomedical research and for assigning DNA and RNA stains in crime scenes to unique individuals.Electronic supplementary materialThe online version of this article (10.1186/s12864-018-4482-7) contains supplementary material, which is available to authorized users.

2 52 Running title: Loss of UGP2 causes a severe epileptic encephalopathy 53 54 55 Abstract: 60 Developmental and/or epileptic encephalopathies (DEEs) are a group of devastating genetic 61 disorders, resulting in early onset, therapy resistant seizures and developmental delay. Here we 62 report on 12 individuals from 10 families presenting with a severe form of intractable epilepsy, 63 severe developmental delay, progressive microcephaly and visual disturbance. Whole exome 64 sequencing identified a recurrent, homozygous variant (chr2:64083454A>G) in the essential UDP-65 glucose pyrophosphorylase (UGP2) gene in all probands. This rare variant results in a tolerable 66Met12Val missense change of the longer UGP2 protein isoform but causes a disruption of the start 67 codon of the shorter isoform. We show that the absence of the shorter isoform leads to a reduction 68 of functional UGP2 enzyme in brain cell types, leading to altered glycogen metabolism, upregulated 69unfolded protein response and premature neuronal differentiation, as modelled during pluripotent 70 stem cell differentiation in vitro. In contrast, the complete lack of all UGP2 isoforms leads to 71 differentiation defects in multiple lineages in human cells. Reduced expression of Ugp2a/Ugp2b in 72 vivo in zebrafish mimics visual disturbance and mutant animals show a behavioral phenotype. Our 73 study identifies a recurrent start codon mutation in UGP2 as a cause of a novel autosomal recessive 74 DEE. Importantly, it also shows that isoform specific start-loss mutations causing expression loss of a 75 tissue relevant isoform of an essential protein can cause a genetic disease, even when an organism-76 wide protein absence is incompatible with life. We provide additional examples where a similar 77 disease mechanism applies. 78 79 80 81 82 83 84 85 86 87 3 Introduction: 88 Developmental and/or epileptic encephalopathies (DEEs) are a heterogeneous group of genetic 89 disorders, characterized by severe epileptic seizures in combination with developmental delay or 90 regression 1 . Genes involved in multiple pathophysiological pathways have been implicated in DEEs, 91 including synaptic impairment, ion channel alterations, transporter defects and metabolic processes 92 such as disorders of glycosylation 2 . Mostly, dominant acting, de novo mutations have been identified 93 in children suffering from DEEs 3 , and only a limited number of genes with a recessive mode of 94 inheritance are known so far, with a higher occurrence rate in consanguineous populations 4 . A recent 95 cohort study on DEEs employing whole exome sequencing (WES) and copy-number analysis, 96however, found that up to 38% of diagnosed cases might be caused by recessive genes, indicating 97 that the importance of this mode of inheritance in DEEs has been underestimated 5 . 98

In eukaryote genomes, the polyadenylation site marks termination of mature RNA transcripts by a poly-adenine tail. The polyadenylation site is recognized by a dynamic protein complex, among which the poly-adenine-binding protein nuclear1 plays a key role. Reduced poly-adenine-binding protein nuclear1 levels are found in aged muscles and are even lower in oculopharyngeal muscular dystrophy patients. Oculopharyngeal muscular dystrophy is a rare, late onset autosomal dominant myopathy, and is caused by an alanine expansion mutation in poly-adenine-binding protein nuclear1. Mutant poly-adenine-binding protein nuclear1 forms insoluble nuclear aggregates leading to depletion of functional poly-adenine-binding protein nuclear1 levels. In oculopharyngeal muscular dystrophy models, increased utilization of proximal polyadenylation sites has been observed in tandem 3′-untranslated regions, and most often cause gene upregulation. However, global alterations in expression profiles canonly partly be explained by polyadenylation site switches within the most distal 3′-untranslated region. Most poly-adenine signals are found at the distal 3′-untranslated region, but a significant part is also found in internal gene regions, like introns, exons, and internal 3′-untranslated regions. Here, we investigated poly-adenine-binding protein nuclear1’s role in polyadenylation site utilization in internal gene regions. In the quadriceps muscle of oculopharyngeal muscular dystrophy mice expressing expPABPN1 we found significant polyadenylation site switches between gene regions in 17% of genes with polyadenylation site in multiple regions (N = 574; 5% False Discovery Rate). Polyadenylation site switches between gene regions were associated with differences in transcript expression levels and alterations in open reading frames. Transcripts ending at internal polyadenylation site were confirmed in tibialis anterior muscles from the same mice and in mouse muscle cell cultures overexpressing expPABPN1. The polyadenylation site switches were associated with nuclear accumulation of full-length transcripts. Our results provide further insights into the diverse roles of poly-adenine-binding protein nuclear1 in the post-transcriptional control of muscle gene expression and its relevance for oculopharyngeal muscular dystrophy pathology and muscle aging.

Developmental and/or epileptic encephalopathies (DEEs) are a group of devastating genetic disorders, resulting in early-onset, therapy-resistant seizures and developmental delay. Here we report on 22 individuals from 15 families presenting with a severe form of intractable epilepsy, severe developmental delay, progressive microcephaly, visual disturbance and similar minor dysmorphisms. Whole exome sequencing identified a recurrent, homozygous variant (chr2:64083454A > G) in the essential UDP-glucose pyrophosphorylase (UGP2) gene in all probands. This rare variant results in a tolerable Met12Val missense change of the longer UGP2 protein isoform but causes a disruption of the start codon of the shorter isoform, which is predominant in brain. We show that the absence of the shorter isoform leads to a reduction of functional UGP2 enzyme in neural stem cells, leading to altered glycogen metabolism, upregulated unfolded protein response and premature neuronal differentiation, as modeled during pluripotent stem cell differentiation in vitro. In contrast, the complete lack of all UGP2 isoforms leads to differentiation defects in multiple lineages in human cells. Reduced expression of Ugp2a/Ugp2b in vivo in zebrafish mimics visual disturbance and mutant animals show a behavioral phenotype. Our study identifies a recurrent start codon mutation in UGP2 as a cause of a novel autosomal recessive DEE syndrome. Importantly, it also shows that isoform-specific start-loss mutations causing expression loss of a tissue-relevant isoform of an essential protein can cause a genetic disease, even when an organism-wide protein absence is incompatible with life. We provide additional examples where a similar disease mechanism applies.

The effect of β-lactoglobulin (β-LG) and κ-casein (CSN3) genotypes on milk composition were evaluated in Iranian indigenous Zel sheep breed. Genotypes were determined by PCR amplification followed by digestion with RsaI enzyme for exon II of the β-LG gene and SSCP method for exon IV of the CSN3 gene. Polymorphism was detected in all PCR products. β-lactoglobulin showed two alleles and three genotypes and CSN3 gene revealed two conformational patterns, respectively. Results indicated that there were significant associations between AB genotype of β-LG gene with higher fat and lactose percentages and also between K 1 pattern of CSN3 gene with higher lactose percentage. Therefore, it is feasible to improve milk composition in Zel sheep breed using β-LG and CSN3 genes.

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The aim of present study was to investigate myostatin gene polymorphism and its association with yearling weight records in Zel sheep using PCR-RFLP and PCR-SSCP methods. Blood samples were collected from 200 Zel sheep, randomly, and DNA was extracted using modified salting out method. Polymerase chain reaction was carried out to amplify 337, 222, and 311 bp fragments, respectively, comprising a part of exon 3, intron 1, and intron 2 of myostatin gene. In addition, exon 3 was digested by HaeIII enzyme under RFLP method, and introns 1 and 2 were studied using SSCP. Under RFLP method, all samples showed mm genotype. Under SSCP method, intron 1 was also monomorph but intron 2 was polymorph (AA, AB, and BB). The allelic frequencies for A and B were 75.5 and 24.5%, respectively. This locus was not in Hardy-Weinberg equilibrium (P < 0.05), and there was no significant effect of myostatin gene on yearling weights.